Safety device for gas producing systems



May 2, 1944. H. B'EDDOES SAFETY DEVICE FOR GAS PRODUCING Filed Dec. 31,1941 l 63 0 60 J7 Z 69 65 6560 1111'. 111;: I -IIZQ/IIIII 198 SYSTEMS 2Sheets-Sheet 1 INVENTOR.

Y fluer 360505066,

May 2, 1944. H. BEDDOES 2,348,104 7 SAFETY DEVICE FOR GAS PRODUCINGSYSTEMS Filed Dec. 51, 194; 2 Shets-Sheet 2 INVENTOR. v

Patented May 2, 1944 SAFETY DEVICE FOR GAS PRODUCING SYSTEMS.

Hubert Bed-does, Chicago, Ill., assignor to Pacific Flush Tank Company,Chicago, Ill'.,. a corporation of Illinois Application December 31,1941, Serial. No. 425,248.-

Claims.

This invention relates generally to safety devices for gas producingsystems and it has to do particularly with a device of this characterespecially well adapted for use in sewage systems of that type whereingas produced in the digestion of sewage is utilized for heating or powerpurposes, or is burned for the purpose of odor control.

In the digestion of sewage a. combustible gas is formed. Such gasisformed at varying rates, depending upon the character of the sewage,the amount of solids introduced into the digester from. time to time andthe size and temperature of the digester. In systems of the foregoingcharacter, more gas may, therefore, be generated than is required forconsumption purposes and it is necessary to discharge. the excess gas toa point of waste consumption. Sewage digestion is usually carried on ina closed tank type digester having either a fixed cover with liquidseals for preventing the escape of gas, or a floating cover of thegeneral type adapted to float upon the liq- Hid in the tank to controlscum formation and aid digestion. In the use of digesters having bothtypes of covers it is highly desirable that the gas be discharged asrapidly as it is generated to avoid the build-up of an excessivepressure in the digester. Otherwise, in the use of a fixed cover typedigester, the excess pressure may break through the liquid seals andallow gas to escape, thereby producing objectionable odor conditions aswell as hazardous explosive conditions. Also, in the use of the floatingcover type digester, an excess gas pressure will cause the cover to riseaway from the body of the digesting material therein with loss ofadvantage of scum control with a consequent loss of efiiciency inoperation of the digester.

To oifset the foregoin objectionable condi tions, it is customary tocontrol the gas formed in the digester in such a way that it isdischarged as it is generated and, if more gas is generated than isrequired at the point of utilization (boiler, etc.) the excess isdischarged to a point of waste where it is burned or otherwise consumed.The utilization device or devices may have their own controlsdetermining the amount of gas required, and there may be times when nogas is required, in which case the gas control must be such as todischarge all gas to a point of waste disposal. In other words, the gascontrols must be such as to discharge all gas to a, point of utilizationor a point of waste or both without pressure back-up in the digester.Separate pressure relief and'flre control devices have heretomaintain.

fore been employed. for the foregoing purpose, one device controllingthe gas flow to the point of utilization and the other controlling, theflow to a point of waste, where the gas is usually disposed of by a mainburner having a constantly burning pilot. The pilot burner is constantlysupplied with gas from the digester. In the use 01 such prior devices,it has been necessary to interconnect the same for the desired gas flowcontrol. Such. prior arrangements have necessitated complicated pipingarrangements which required considerable skill in setting up the sameand which at all times invited hazardous explosive conditions due toimproper installation. They were also quite expensive to install and to.dition to further complicating the piping arrangement.

One of the objects of my invention is to provide improved safety controlmean of the foregoing character by which all of the foregoingobjectionable conditionsare avoided.

Another object is to provide an improved safety control device forcontrolling gas generated in a sewage digester, which device is ofsimple and inexpensive construction, is of compact form, is soeasy toinstall that it may be installed by unskilled labor without danger ofexplosions through improper piping, is foolproof from the safetystandpoint, is easy to maintain, is adapted to 4 prevent backfiring, andis adapted to maintain proper gas pressure conditions in a more positiveand eflicient manner than heretofore.

A further object is to provide a single safety device for controllingthe flow of gas to a point of utilization or to a point of waste or toboth.

. which device is so constructed and arranged that all pipe connectionsare direct without interconnections.

Still another object is to provide a device of the foregoing characterwherein a single flame arrester is employed for controlling the flow ofgas to a point of utilization, a point of Waste consumption, and to apilot burner, the arrangement being such that the flame arrester isdisposed between the gas source and all gas flow controlling means.

Other objects and advantages will become ap nection with a sewage systemof the type shown" in Fig. 1. Such system may include a digester I ofthe general type disclosed in the above-.-

mentioned Downes patent. This digester includes a floating cover Hhaving a central'gas dome I2 wherein gas generated in the digestion ofthe sewage is collected. The'cover' H is arranged to float on the top ofthe material I3 contained in the tank and, as hereinabove explained, itis desirable that the gas generated and received in the dome bedischarged as rapid- 13} as it is'generated, otherwise, the cover may beraised bythe excess pressure above the material" 13 with theobjectionable results'a'lready explained.

It is customary to usethe gas generated in the digester in the operationof the sewage system. It'may be used in a boiler whichis employed forheating purposes, such, for example, as supplying heating coils l4located in the bottom of the digester for the purpose of increasing thedigestion action. To the foregoing end, there'is employed ;a dischargepipe I 5 leadingfrorn the gas dome l2 downwardly throughthe digestingmaterial l3 and thence outwardly to a pressure relief device l6 withwhich my invention is particularly concerned. From the device I6 the gasis fed through pipes I! to apointof utilization which, in this case, isaboiler 8 tha't is directly connected through circulatingpipes l9 and 20to the digester heater coils i4. The pressure control device I5, is,also directly connected through pipe 2| to a waste burner 22,,which maytake any suitable well-known form. A There is also a pipe connection 23leading directly from the pressure relief devicelB to a pilot burner(not shown) associated with the waste burner 22, which pilot burner maytake any suitable and well-known form.

The boiler l8 may include its own controls (not shown) for determiningthe amount of gas to be consumed thereby. If the amount of gas generatedin thedigester exceeds the requirements of the boiler l8, the excess gasis discharged by the pressure relief device l6 to the waste burner whereit is consumed; In this way, the gas generated in the digester isconstantly discharged and maintained at a maximum pressure which willnot disturb the proper operation of the cover II. It will be seen fromthe foregoing, and by referenceto Fig. 1, that all of the pipeconnections through which the gas flows are direct connections leadingfrom the pressure relief device I6 and that all such connections are soarranged that they may be made simply and without the necessity of crossconmotions for pilot control or otherwise.

The pressure relief device I5 is so constructed and arranged that onlyone such device need be employed in the system while, at the same time,gaining all of the advantages from the standpoints of pressure reliefand flame arresting that were obtained with prior multiple devices. Thedevice shown in detail in Fig. 2 includes a casing having a gas inlet 3|to which is connected the inlet end of pipe l5 leading to the digesterl0 (Fig. 1). The inlet end of the casing 30 is provided with a chamber32 having an enlarged opening 36 in its upper part in which is mounted aflame arrester unit 33. This flame arrester is of cylindrical form andit comprises an outer ring member 34 having an annular'flange 35 at itsupper edge seated upon the upper wall of the casing 30. The ring 34 isprovided with an internal web portion havinga central axial ring section31 which guidingly receives a tubular conduit member 38 having conduitmember 38.

at its upper end a plurality of radial arms 39 which seat upon the upperedge of the ring 34. Confined btween'the ring 34 and the member 38 is aflame arrester unit 40 of the well-known ribbon type having a pluralityof vertically extending, narrow gas passageways 4|.

The casing 30 is provided with a second chamber 42 which is connected bypipe I! to the boiler I8. The upper wall 42 of the chamber 42 isprovided with a threaded opening 43 in which is received a flangedbushing 44 that'guidingly receives and supports the lower end of thetubular The tubular body of the member 38 is long enough to projectslightly below the bushing 44 so that its lower end serves as an annularseat against which a valve 45 is adapted to seat under circumstanceswhich will be explained hereinafter. The flame arrester unit 33 iscovered by an annular dome-shaped casing section 46 having an annularflange 46 secured to the upper side of the casing 30 with its domeportion disposed over the flame arrester unit 33 and forming thereabovea'chamber 41. With this arrangement the chamber 32 is separate anddistinct from the chamber 42, being connected therewith only through theflame arrester element 48 and the tubular member 38.

The valve 45 is held open at all times except in the digester It! shouldbecome ignited. In that case means are provided for causing the valve 45to close and thereby shut off the connection between the boiler I8 andthe gas source. Specifically, the valve 45 includes a stem 48reciprocably supported in a valve guide 49 carried by the bottom of thecasing 30. A tension spring 50 having one end connected to the lower endof the valve stem 48 and its other end connected to the valve guide 49constantly urges thevalve stem 48 and the valve 45 upwardly toward aclosed position against the lower end of the tubular member 38. Closingmovement of valve 45 is normally prevented by a stem 5| so mounted thatits lower end abuts the upper side of the valve 45 and its other end isreceived in a bore in a bushing 52 threadedly received in and carried bythe dome section 46. The stem 5| is provided nearits upper end with anannular groove supporting a ring of fusible material 53 which is adaptedto melt, for example, at a temperature of from 300 to 400 F. This ring53 is of larger diameter than the bore of the bushing 52 so that whenthe ring 53 is in place it abuts the lower edge of the bushing 52 andholds the stem 5| and valve 45 in the open position shown in Fig. 1.However, if the gas should become ignited on the boiler side of theflame arrester element 40, the heat developed would in a very short timemelt the ring 53 releasing the stem| so that the springill will movetllezsame and the valve 45 into seating engagement with the lower end ofthe member, 38, thereby cut-' ting off the gas flow between the boiler18 and. the gaszsource. In case of fireythe flame. arrester 40 is ofsuch. construction, as iswell known, that-it will prevent backfiringtherepast, and the flame arresting action. is fully effective for aperiod of time sufficient to permit melting of the fusible ring 53. Inother words, the ring 53 will melt and the valve 45 will be, closedbefore the flame arrester element 40 becomes ineffective toprevent theflame to pass thereby.

A pressure relief means is also mounted in the casing Won the boilerside of the flame arrester unit 33. The arrangement is such that if theboiler- IB-orotherpoint of utilization is'not handlingall ofthegasgenerated, the pressure relief mechanism will function to dischargethe excess gas to the Waste burner 22 (Fig. 1). More particularly thecasing 38 is provided with another chamber 54 which is connected by thepipe 2! (Figs. 1 and 2) to the waste burner 22. The upper wall 42 ofchamber 42- is provided with an opening in which is threadedly mounted abushing 55 serving as a seat for a valve 5E'Whi0h controls communicationbetween the cha-mber s GZand 54. The valve 58 is normally held closedexcept when the gas pressure at the digester and in the chambers 32 and42' exceeds a predetermined amount.

Valve 56 is controlled by pressure meanswhich includes a flexibleweighted diaphragm 51 mounted in a casing section 53 disposed abovethechamber 54-. The casing section 58 is divided into two parts 58 andStl -haVing annular flanges 59 and 59 secured together by stud-and-boltdevices 65! and between which the edge of the diaphragm 51 is secured.In this way the casing section 58 is divided into chambers 61 and 62,one above the diaphragm 57 and vented to atmosphere through an outlet63, and the other beneath the diaphragm and connected to the inletchamber through a. conduit 6d. Valve 55 is provided with a stem 55 whichextends upwardly and slidably througha bushing 65 secured in an openingin the bottom of the casing section 58 The upper end of the stem 65 isconnected to the diaphragm 51 by a plate member 51 fixed to the stem 65and engaging the underside of the diaphragm and a plate member 68engagin the upper side of the diaphragm and fixed to the stem by asleeve 69 and nut iii. The diaphragm is weighted by one or more platesit supported by plate 68 for holding the valve 56 closed except when apredetermined pressure is present in chamber 52 and acting on theunderside of the diaphragm to raise thelatter and, in turn, the valve56.

The pilot burner (Fig. l) for the waste burner 22 is constantly suppliedwith gas from the chamber 42 through pipe 23. In this way the pilotburner is directly connected with the gas source by Way of the valve 45so that it burns constantly and is ready for ignition of the gas in thewaste burner 22 when the valve 55 opens and discharges excess gas towaste. The bottom portions of the chambers 52 and 42 are provided withdrain outlets ?2 and 73 for removal of condensation that may be formedin these chambers. These drain outlets may be normally closed bymanually operable valves (not shown) or any other suitable means.

Briefly, the operation of the foregoing structure isas follows: Thevalve lfibeing normally open, gas flows from the digester lothrough the.pipe 25 happens, the pressure in chamber 62, which is the same as thepressure in chamber 32 and at the source,.raises the diaphragm 57,opening the valve 56 and discharging the excess gas from the chamber 42into the chamber 54 and outwardly through the pipe 2| to the wasteburner 22. As soon as the pressure. in chambers 62 and 32 is'loweredbelow the maximum, the valve 56 closes so that gas is. then fed only tothe point of utilization. If the gas should for any reason becomeignited and tend to burn back toward the digester, the flame arresterifl will prevent passage of the burning gases into the chamber 32 andeventually the fusible ring 53 will release the stem 5! and permit thevalve, 45 to close. When the valve 45 is. closed, all danger of firereaching the chamber 32 and the digester through the pipe I5 is avoided.If such a condition should happen, operation may be re-- sumed byinstalling a new fusible ring 53 to hold the .valve 45 in its openposition.

InFig. 3 I have shown another form of pressure relief device embodyingmy invention. In this form, the parts are compactly arranged bydisposing the waste control valve and diaphragm operating structure insuperimposed relation upon the inlet valve and flame arrester structure.This form includes an annular casing structure having a lcwersection 8!!supporting a flame arrester unit BI and an inlet valve 82. The bottom ofthe section is provided with an opening til in which is received abushing 83, the upper rim of which serves as a seat for the valve 82.The bushing 83 is provided with an annular flange 83* which extendsunder the bottom of the section 89 and is clamped in place thereon by aring section 84 having a threaded opening 84 to which one end of theinlet pipe !5 leading to the digester is connected.

The flame arrester unit comprises outer'and' confined a body of porousrefractory material 81 which serves as a flame arresting element. Thismaterial is sufficiently porous to permit the flow of gas therethroughwhile preventing backfiring or the like as in the case of the flamearrester element 4B of the first form. The body 81 is secured to therings 85 and 86 by any suitable cement material such, for example, aslute. The bonding together of these parts is facilitated by providingannular grooves 85 and 86 in the inner faces of the rings Biand 86 andchannels 87% and 8'l in the inner and outer peripheries of the body 81,which grooves and channels are filled with the cement. The flamearrester unit 35 is supported in the upper portion of the casing section813 by mounting the ring 85 upon an annular casing ledge 83 and bysupporting the inner ring 85- ber 89 seated on the upper edgeof theinner ring 88 and clamped in place by stud bolts 90 passing through theplate 69 and engaging the ribs 88.

The valve 82 is provided with a stem 93 which extends upwardly through adepending tubular guide 92 integral with the plate 89. A spring 93 isdisposed in the tubular guide 92 under-compression so that it tends tourge the valve 82 downwardly against its seat 83, as shown in dottedlines in Fig. 3. It is restrained againstsuch movement, however, byextending the valve stem 9| upwardly through an opening in the plate 89and by providing its projecting end portion with an annular groove 94 inwhich is received a fusible ring 95 of larger diameter than the plateopening through which the stem passes. This fusible ring 95 is similarto the fusible ring 53 of the first form and holds the valve 82 openexcept in case of fire which will melt the fusible ring releasingthevalve stem for movement by the spring 93 to close the valve 82. Toinsure a more rapid pickup of heat from gases burning at the upper sideof the flame arrester, I provide a hollow cage-like member 96 threadedupon a central projection 89* on the upper side of the plate 89 throughwhich the valve stem 9! passes. This cage 96 houses the projecting endof the valve stem 9I and it is providedwith a plurality of radial fins9'! which insure a rapid pickup and transfer of heat to the plate 89 andthe connected parts, thereby insuring a rapid transfer of heat to thefusible ring 95.

An intermediate casing section I is mounted directly upon the casingsection 80, being secured thereto by a plurality of annularly arrangednutand-bolt devices II; This casing section is pro vided with an innerchamber I02 which is connected by a pipe I'I to the boiler or otherpoint of utilization. This chamber I02 is also connected through passageI03 and pipe 23 to a pilot burner associated with a waste gas burnersuch as shown'in Fig. 1. In the normal operation of the device and solong as the gas generated in the digester is being used or consumed bythe boiler or the like, gas will flow from the digester through the pipeI past the valve 02 into the chamber 80 below the flame arrester 8 I,through the flame arrester element Bl into the chamber I02 andthrough'the pipe I 'I' to the boiler. However, in case the pressure ofthe gas in the digester exceeds the maximum of, for ex ample, four andone-half inches, means are provided for discharging the excess gas to awaste burner as in the first-described form. Specifically, the casingsection I00 is provided with an outer chamber I04 surrounding thechamber I02. The upper end of the inner chamber I02 is connected to theouter chamber I04 through an opening in which is mounted a bushing I05serving as a seat for a pressure relief valve I05; The outer chamber I04is adapted to be connected to a waste burner through a pipe 2P A thirdcasing section I01, in which is mounted a diaphragm I08, is superimposeduponthe casing section I00. The section I0! is provided with a partitionI09 which closes the upper end of the chamber I04 and which is providedwith a central opening receiving a threaded valve stem guide I I0. Thevalve I06 is provided with a stem III which slidably passes through theguide H0 and is connected to the diaphragm I08 in a manner similar tothat connecting the valve stem oi the valve 56 with the diaphragm 5'! ofthe first form. By the foregoing arrangement, a chamber I I2 is formedbeneath the diaphragm I00, which chamber is connected with the inletchamber 80 by a pipe II3. When the maximum pressure to be maintained inthe digester is exceeded, through the generation of an excess amount ofgas or through reduction in the boiler requirements, the pressure inchamber II2 raises the diaphragm I08 and, in turn, the valve I06 and:discharges the excess gas into chamber I04 and thence through the pipe2 I to the waste burner.

Other than just described, the construction and operation of this formof device is substantially the same ,as the form of Fig, 2.

I believe that the operation and advantages of my invention will be wellunderstood from the foregoing description. My invention overcomesresults due to backfiring from the point of utilization or from a wasteburner or from a pilot burner. The device is of such character that pipeconnections leading thereto and therefrom may be very simply made and donot require the use of skilled labor in making the same. Mistakes inpiping are avoided by the simplification of piping, thereby avoiding thehazardous conditions due to improper piping that exist in priorstructures. Furthermore, my invention greatly increases the eificiencyof gas control, insuring proper and most efficient operation of thedigester at all times.

I claim:

1. In a device of the character described, a casing havin an inletconnection, and at least two separate discharge connections, a valve controlling the flow of gas between said inlet connection and one of saiddischarge connections, flame arresting means between said inletconnection and said one discharge connection, heat controlled means fornormally holding said valve .open, a second valve between said onedischarge connection and another of said discharge connections, andmeans normally holding said second valve closed to prevent discharge ofgas through said other discharge connection, said means being controlledby pressure at said inlet opening to open said second valve when thepressure at said inlet is increased to a predetermined extent.

2. In a device of the character described, a casing having an inletchamber with an inlet connection, a main discharge chamber having adischarge connection, a waste discharge chamber having a dischargeconnection and a pressure chamber connected to said inlet chamber, avalve controlling the flow of gas from said inlet connection to saidmain discharge chamber, heat controlled means normally holding saidvalve open, flame arrester means between said inlet and main dischargechambers, a second valve-between said discharge chambers, and a weighteddiaphragm mounted in said pressure chamber subject to the pressure insaid inlet chamber and connected to said second valve, the arrangementbeing such that when the pressure in said .inlet chamber and, in turn,said pressure chamchamber into said waste discharge chamber and outthrough its discharge connection.

3. In a system of the character described, a

gas generating source, gas utilization means, a

waste gas burner and a pilot burner for the waste gas burner,andipressure relief Jmeans which comprises a casing 'havingan inletchamber 'con-' nected to the gas source, a discharge chamber connectedto the gas utilization means and to the pilot burner, a second dischargechamber connected to the waste burner, and a pressure chamber constantlyconnected to 'said inlet chamber, acvalve between said inlet and firstdischarge-chambers, heat control means normally holding said valve inopen position, a second valve between said discharge chambers, pressurecontrolled means located in said pressure chamber and normally holdingsaid second valve closed so that gas flows normally only to'the uti'lization means and pilot burner, the arra'ngementbeingsuch that when thepressure in said inlet chamber exceeds a predetermined amount, saidpressure controlled means is actuated to open said second valve anddischarge gas to the waste burner.

4. In a system of the character described, a gas generating source, gasutilization means, a waste gas burner and a pilot burner for the wastegas burner, and pressure relief means which comprises a casing having aninlet chamber connected to the gas source, a discharge chamber connectedto the gas utilization means and to the pilot burner, a second dischargechamber connected to the waste burner, and a pressure chamber constantlyconnected to said inlet chamber, a valve between said inlet and firstdischarge chambers, heat control means normally holding said valve inopen position, a second valve between said discharge chambers,

v pressure controlled means located in said pressure chamber andnormally holding said second valve closed so that gas flows normallyonly to the utilization means and pilot burner, the arrangement beingsuch that when the pressure in said inlet chamber exceeds apredetermined amount, said pressure controlled means is actuated to opensaid second valve and discharge gas to the waste burner, and a singleflame arrester device, mounted in said inlet chamber between said firstvalve and the gas source and simultaneously serving to prevent back-firefrom the point of utilization, the pilot burner and the Waste burner.

5. In a structure of the class described, comprising a casing dividedinto an inlet chamber and adapted to be connected to a gas source, adischarge chamber connected to said inlet chamber and adapted to beconnected to a gas utilization means, a second discharge chamberconnected to said first discharge chamber and adapted to be connected toa waste burner, and

a pressure chamber connected with said inlet chamber for equalization ofpressure therein, a valve controlling communication between said inletand first discharge chambers, heat controlled means for normally holdingsaid valve in open position, a valve for controlling communicationbetween said discharge chambers, a pres sure actuated device in saidpressure chamber normally holding said second valve closed and adapted,upon a predetermined increase in the pressure of the gas in said inletand pressure chambers, to open said second valve, and a single flamearrester means in said inlet chamber where it is disposed between thegas source and said discharge chambers.

6. In structure of the class described, a casing divided to provide aninlet chamber having an inlet connection, and a discharge chamberhaving. a discharge connection, ,flarne arresting meansiin said; inletchamber/for controlling .the flow of gas to said discharge chamberwhichsincludes .a tubular member extending. from the side of said meansopposite saidinletlconnection into saiddischarge'chambe'r and providinga valve seat at its discharge end, a valve insaid .discharge chamber,spring means urging said valve toward said valve seat, and heatcontrolled means forholdingsaid valve open to interconnect saidchamberswhich includes a stem member slidably. engage'di with thecasingat oneend and said valve at .the other. end' ,iand. a fusible ring .imembe'r:carried by said stem and engaging said casing'normallyspreventingi.slide movement of said stem in. said casing andthereby holding said valve open, said ring member being adapted uponbeing heated to a predetermined extent to fuse and release said stem andpermit said spring means to close said valve.

7. In structure of the class described, a casing having partitionsdividing it into an inlet chamher having an inlet connection, a maindischarge chamber having a discharge connection and a waste dischargechamber having a discharge connection, flame arrester means in saidinlet chamber, a valve in said main discharge chamber controllingcommunication between said inlet and main discharge chamber, heatcontrolled means normally holding said valve open, a valve in said wastedischarge chamber controlling communication between said dischargechambers, and means normally holdingsaid second valve closed, said meansbeing controlled by the gas' pressure in said inlet chamber for openingsaid second valve when a predetermined pressure is present in said inletchamber.

8. In structure of the class described, a casing having partitionsdividing it into an inlet chamber having an inlet connection, a maindischarge chamber having a discharge connection, a waste dischargechamber having a discharge connection, and a pressure chamber connectedto said inlet chamber, flame arrester means in said inlet chamberbetween said inlet connection and the connection between said inlet andmain discharge chambers, a valve in said main discharge chambercontrolling communication between said inlet and main dischargechambers, heat controlled means normally holding said valve open, avalve in said waste discharge chamber controlling communication betweensaid discharge chambers, and means normally holding said second valveclosed, including a diaphragm in said pressure chamber connected to saidsecond valve and weighted to a predetermined extent to normally holdsaid second valve closed, said diaphragm being adapted to be raised toopen said second valve when the pressure in said inlet and pressurechambers is increased to a predetermined extent.

9. In structure of the class described, a casing having a lower or inletchamber, a main discharge chamber superimposed upon said inlet chamber,a waste discharge chamber surrounding said main discharge chamber, and apressure chamber superimposed upon said waste discharge chamber, meansconnecting said pressure chamber with said inlet chamber, a valvecontrolling the inlet of gas to said inlet chamber, flame arrestingmeans between said inlet and main discharge chambers, heat controlledmeans supported by said flame arresting means for normally holding saidvalve open and adapted to close said valve when a predeterminedtemperature is reached 1 in said main discharge; chamber, a second-valvein said waste discharge. chamber, and :means located. injsaid pressure.

tion adapted to be connectedlto a gas source, an

intermediate section having an inner discharge chamber having aconnection adapted to be connected to a point of gas. consumption, andan outer: discharge chamber adapted to be con-,

nected to a point of waste, an upper section having a pressure chambertherein, means connecting said pressure chamber with said inlet chamber,a valve controlling the flow of gas into said inlet chamber, flamearresting means between said valve and said inner discharge chamher, asecond valve controlling the flow of gas betweensaid discharge chambers,and pressure controlled means in said pressure chamber connected to saidsecond valve and adapted when subjected to a predetermined pressure tomove said second valve to an open position and adapted when subjected toa predetermined lower pressure to close said second valve to closecommunication between said discharge chambers.

' HUBERT BEDDOES.

